How to create a WebSite (in HTML and CSS) - STEP #2 PART #2

/* Lesson by AceSomme#1234 */

/* Welcome to the second part of the second lesson ! */
/* This time, we are going to do CSS */
/* So create a new file and rename your file "styles.css" */
/* Subscribe to my YouTube channel for more tutorials ! https://direct-link.net/32476/mytc */

/* \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ */
/* > Go follow the first part : https://direct-link.net/32476/1p2l < */
/* /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ */

body{
    font-family: 'Source code pro', Calibri, serif;
    margin: 0px;
    padding: 0px;
}

nav{
    width: 100%;
    background-color: #424558;
}

nav > ul{
    margin: 0px;
    padding: 0px;
}

nav > ul::after{
    content: "";
    display: block;
    clear: both;
}

nav li{
    list-style-type: none;
}

nav > ul > li{
    float: left;
    position: relative;
}

nav a{
    display: inline-block;
    text-decoration: none;
    padding: 20px 30px;
    color: #FFF;
}

.menu-index:hover{
    border-top: 5px solid #e44d26;
    background-color: RGBa(228, 77, 38, 0.15);
}

.menu-second:hover{
    border-top: 5px solid #0070bb;
    background-color: RGBa(000, 112, 192, 0.15);
}

.menu-third:hover{
    border-top: 5px solid #f1dc4f;
    background-color: RGBa(241, 211, 79, 0.15);
}

/* Made by AceSomme#1234 : https://www.youtube.com/channel/UC14X3SnN82Bh4_YbQ6nysvQ?view_as=subscriber */

.menu-fourth:hover{
    border-top: 5px solid #BBB;
    background-color: RGBa(220, 220, 220, 0.15);
}

.menu-five:hover{
    border-top: 5px solid #29a329;
    background-color: rgb(51, 204, 51, 0.15);
}

nav li:hover a{
    padding: 15px 30px 20px 30px;
}

.submenu{
    display: none;
}

nav li:hover .submenu{
    display: inline-block;
    position: absolute;
    top: 100%;
    left: 0px;
    padding: 0px;
    z-index: 1000;
}

.submenu li{
    border-bottom: 1px solid #CCC;
}

.submenu li a{
    padding: 15px 30px;
    font-size: 13px;
    color: #222538;
    width: 270px;
}

.menu-second .submenu{
    background-color: RGBa(000, 112, 192, 0.25);
}

.menu-third .submenu{
    background-color: RGBa(241, 211, 79, 0.25)
}

.submenu li:hover a{
    color: #eee;
    font-weight: bold;
}

.menu-second .submenu li:hover{
    background-color: RGB(000, 112, 192)
}

.menu-third .submenu li:hover{
    background-color: RGB(175, 175, 75)
}

/* Lesson by AceSomme#1234 */